<!-- Begin
function cover(form) {
a=eval(form.a.value);
s=eval(form.s.value);


PCD=Math.round((s/a)*100)/100;

form.PCD.value = PCD;
if (form.PCD.value > 220) form.PCD.value="Error";
if (form.PCD.value < 50) form.PCD.value="Error";
if (form.PCD.value == "NaN") form.PCD.value="";

}
//-->